This patent application claims priority based on Japanese patent application, H11-109977 filed on Apr. 16, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a probe card which is used for testing electric characteristics of electric components such as IC chip and LSI chip and so on, and in particular to the probe card in which position accuracy and signal quality of probe needles thereof are increased.
2. Description of the Related Art
FIG. 1 is a cross sectional view of a conventional probe card. The conventional probe card is comprised of: a printed circuit 10; a plurality of probe needles 20 (20a and 20b), a plurality of soldering portions 24 (24a and 24b); a plurality of fixing resin portions 26 (26a and 26b); and a plurality of fixed bases 28 (28a and 28b). The printed circuit 10 includes a plurality of transmission lines 22 (22a and 22b). The probe card is used for performing an electric characteristic test (probe test) of electric components such as IC chip, LSI chip and so on.
The probe needle 20 is of a cantilever type being supported in an open-sided manner. A plurality of probe needles 20a and 20b are supported by a plurality of fixed bases 28a and 28b, whose cross sections are triangular, in a tilted manner. After the position of the probe needles 20 is adjusted manually, the probe needles 20 are fixed by a plurality of fixing resin portions 26a and 26b. The respective probe needles 20a and 20b are connected to the respective transmission liens 22a and 22b by soldering portions 24a and 24b, respectively.
When a board whose position accuracy is low such as a glass epoxy board is used as the printed board 10, there is caused a problem in that the position of the probe needle 20 has to be manually adjusted when connecting the probe needle 20. Moreover,when using the board of low position accuracy, it is difficult to make narrow a pitch and an interval between a plurality of probe needles 20a and 20b. 
Therefore, it is an object of the present invention to provide a probe card and a manufacturing method therefor which overcome the above issues in the related art. This object is achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention.
According to one aspect of the present invention, there is provided a probe card which comes in contact with electrodes of electric components so as to test characteristics of the electric components, the probe card comprising: a printed board having a plurality of first transmission lines; a build-up board, attached on said printed board, which includes a plurality of second transmission lines connected to a plurality of the first transmission lines, respectively; and a plurality of probe needles connected to a plurality of the second transmission lines so as to come in contact with the electrodes of the electric components.
Preferably, the printed board includes a flat portion and a central protrusion provided on a substantially central surface of the flat portion, and the build-up board is attached on the central protrusion.
Moreover, the build-up board is preferably made in a film-like shape and is attached to the printed board in a fully strained manner.
Moreover, the build-up board is preferably made of an epoxy material.
Preferably, each of a plurality of the first transmission lines includes a plurality of first and second pads at both ends thereof, each of a plurality of the second transmission lines includes a plurality of third pads at each end thereof, and each of a plurality of the second pads is connected to each of a plurality of second transmission lines, and a plurality of the third pads is connected to a plurality of the probe needles.
Moreover, it is preferable that a plurality of the probe needles has elasticity in vertical directions and such that one end connected to each of a plurality of the thirds pads is displaced in horizontal directions from other end which comes in contact with each of the electrodes.
According to another aspect of the present invention, there is provided a method of manufacturing a probe card for use in testing characteristics of electric components, the method comprising: forming a first transmission line in a first substrate; superposing a second substrate on the first substrate; forming a second transmission line to the second substrate; cutting the first and second substrates in a predetermined shape; and forming a probe needle on the second substrate.
In the method in which the first substrate includes a flat portion, a substantially central protrusion provided on a top surface of a substantially center of the flat portion and a peripheral salient which is disposed away from the central protrusion with a predetermined distance away and which is provided on the top surface of a peripheral-side flat portion, the cutting preferably includes: cutting the second substrate a long a periphery of the central salient, and cutting the first substrate along an inner periphery of the peripheral salient.
Moreover, the forming the probe needle preferably includes forming simultaneously a plurality of the probe needles.
Moreover, the forming the probe needle preferably includes: fixing, by a bonding machine which fixes a wire on a substrate, a tip portion of the wire to the second substrate; and cutting a portion above the tip portion of the wire by heating the portion.
This summary of the invention does not necessarily describe all necessary features so that the invention may also be a sub-combination of these described features.